Safety chain as defined in SAE J684 of June 2004 is an assembly which provides a secondary means of connection between the rear of the towing vehicle and the front of the trailer or towed vehicle, for the purpose of retaining connection between the towing vehicle and the trailer in the event of separation of the trailer coupling form the ball or the ball from the hitch, long enough to bring the vehicles to a stop. Two safety chains shall be permanently fastened to each side of the trailer tongue.
